This invention relates to a label applicator. It relates more particularly to an applicator which strips labels successively from a tape and automatically applies them to successive objects.
There are many different types of label applicators is use today. Often, the labels to be applied are adhered to a backing strip or tape which is wound into a roll. The applicator advances the strip over the knife edge of a stripper plate. The label, being somewhat stiff, tends to remain flat and continue in the same direction so that it peels from the strip.
Many prior applicators also have an extensible pressure foot which picks up the label as it separates from the strip and presses it down against an object. When the next object is brought into position, the strip is advanced by a predetermined amount to bring the next label into position to be picked up by the pressure foot. Examples of such applicators are shown in U.S. Pat. Nos. 3,450,590; 2,489,837; 3,736,208; 3,769,139; 3,405,021 and 3,436,294.
Prior label applicators of this general type are not entirely satisfactory for a variety of reasons. Some are not able to properly apply a label to an article which is relatively sharply curved in one or more directions, such as a pen or paint brush handle, for example. While the middle of the label adheres to the article, its edges do not, with the result that they catch on something and are pulled away from the pen or handle.
Other conventional applicators do not position the label accurately enough on the article. This becomes a problem if the article or package has a particular spot especially designed to receive the label. Only a few thousandths of an inch error may cause the label to cover advertising matter on the article or overhang one of its edges or otherwise disfigure the article.
The major reason for the inability of the prior applicators to properly position the label is due to the fact that they do not control the advance of the label strip accurately enough to properly position successive labels for application to successive articles. Some rely on photoelectric devices to stop the advance when they detect each label. However, position errors arise if the colors of the labels and backing strip are too similar and, in the case of labels which are more or less transparent, this type of applicator cannot be used at all. Other label applicators use mechanical devices such as a spring-like finger or star wheel sensor to detect the leading edges of successive labels to control tape advance. However, position errors arise there because the label thickness may vary so that the leading edges of some labels are not sensed. Faulty operation will also occur with labels that are too thin.
Other applicators of this type are disadvantaged because they are excessively complicated, bulky or expensive.